We can assign a material to individual parts from the assembly environment. Follow these steps to do so:

1. Decide which part you would like to assign/adjust to/for the material.
2. Expand the part from the design tree. Then, select Edit Material, as shown in the following image:

3. Assign or adjust the assigned material as needed.

Note that, once we assign the material to the parts, it will be updated in the original part file, since they are now linked. 

4. We can assign the same material to more than one part in one go by highlighting the parts, right-clicking, and then selecting the desired material, as shown in the following screenshot:

 This concludes editing a part's material assignments within an assembly file. When editing materials in an assembly, take note of the following points:

• If we change the material within the assembly and save it, the part's material assignment will be updated as well. This is because the parts and the assembly file are connected.
• If we edit the material assignment for a repeated part (that is, we have more than one copy in the assembly), all the part's materials will be updated to match the new edit.

Now that we have materials assigned to our parts, we can start evaluating our mass properties.